Risk assessment for listeriosis in consumers of Parma and San Daniele hams

Following the detection of Listeria monocytogenes in samples of dry cured ham imported in the USA from Italy, the Italian Ministry of Health planned a risk assessment for listeriosis in ham consumers. The risk assessment was performed according to international guidelines set by FAO and WHO. Expected incidence of illness was 4.7 × 10−10 cases per serving in the case of normal adult population, 6.1 × 10−7 in the case of organ transplanted patients, the most susceptible risk sub-population. Due to the low value of water activity even in the deeper parts of the ham, bacterial growth had a very slight effect on the probability of illness.